At total of 45 of them have gone on to commit further crimes in Britain, including 14 who have gone on to kill, 13 who have committed sex offences and nine who carried out violent assaults.

Dominic RaabCredit:
Rex Features

The cases include that of Arnis Zalkans, a Latvian suspected of murdering 14-year-old schoolgirl Alice Gross before killing himself. Before entering Britain he served seven years in prison in his home country for murdering his wife.

In another high-profile case Adelhamid Abaaoud, a Belgian citizen who orchestrated the Paris terror attacks, entered Dover last year despite being subject to an arrest warrant.

In several of the cases senior judges expressed their astonishment that the offenders had been allowed into Britain despite the severity of their offences.

The analysis added to the deepening row within the Conservative Party over Europe as David Cameron has repeatedly argued that Britain will be safer if it votes to stay in.

Vote Leave claimed the European Union is "hanging out the welcome sign" to foreign criminals.

Dominic Raab, the eurosceptic justice minster, said: "European Union rules make it far too difficult to control who comes into the UK, and who we can deport. In security terms, that forces us to import risk, at the expense of public protection. There's no escaping the fact that this weakens our security."

A poster for Alice Gross attached to a lampost in central London and (inset) Arnis Zalkalns, the man police want to traceCredit:
Getty Images

However Damian Green, a Conservative MP and former Home Office minister who is campaigning for Britain to stay in, said that since 2010, 6,000 European citizens have been barred from entering the UK

He said: "Once again, the Leave campaign's argument makes no sense, it is a mix of chaos and confusion.

"The truth is that the UK already has the best of both worlds. We maintain all the benefits of EU membership while opting out of the passport-freeSchengen area and maintaining our border at Calais rather than Dover."

The analysis is also likely to prove controversial as the family of Alice Grosspreviously said they did not want their daughter's death "hijacked" by anti-immigration groups.

In a statement released through Liberty, the civil rights group, ahead of her inquest last year the family said that they "believe in freedom of movements and human rights".

Foreign offenders have entered the UK under Europe's "free movement" laws, which entitle EU citizens to travel and work across Europe.

While Britain can bar foreign offenders from entry if they are deemed to pose a "serious threat" to public security, European nations are not compelled to share the criminal records of their offenders.

In some of the most serious cases foreign offenders were allowed to enter Britain because the authorities had not been informed that they had committed serious crimes in their home country.

Vote Leave also highlighted concerns that while convicted murderers in the UK are subject to supervision for the remainder of their life on release, the same approach does not apply to those convicted of murder in other EU states.

As well as Zalkans, the 45 criminals from the EU who have committed further offences in the UK include Victor Akulic, a Lithuanian who raped a 40-year-old woman and then forced her to watch a recording of the horrific attack just months after arriving in the UK in 2010.

Immigration has overtaken the NHS as the most commonly mentioned worry of the British voter, according to an Ipsos Mori pollCredit:
Rex

In 2012 Kajus Scuka, a murderer from the the Czech Republic who had served 11 years for murdering his wife in his home country, was jailed for a series of sex attacks including a knifepoint rape.

Until he was caught, police did not even realise that he was in the country. Judge Peter Kelson said at the time: "It seems to me [to be] the case that even with your convictions for murder and assaults you were free to enjoy the same freedom of movement as any other European citizen."